Height effect on nucleation-site activity and size-dependent bubble dynamics in microchannel convective boiling

Man Lee, Luthur Siu Lun Cheung, Yi Kuen Lee, Yitshak Zohar

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Forced convection boiling in microchannels is studied experimentally under the uniform heat flux boundary condition. Several microchannel heat sinks with integrated temperature sensors, spanning two orders of magnitude in height 5-500 νm, have been fabricated with designed nucleation sites on the bottom surfaces. The microchannels are capped by a glass wafer to monitor bubble activity using video microscopy. Distributed micro heater elements on the device backside are used as the heat source, while the working liquid flow rate is adjusted using a syringe pump. The boiling curves of the device temperature as a function of the input power have been measured for various flow rates. The curves for increasing and decreasing heat flux exhibit a hysteresis loop, while the conditions corresponding to the onset of nucleate boiling and critical heat flux (CHF) are clearly distinguishable. The activity of nucleation sites as well as the ensuing bubble dynamics, from incipience to departure, is found to depend on the channel height. The critical size above which a nucleation site is active, along with three aspects of bubble dynamics, namely growth rate, departure size and release frequency, have been characterized experimentally and proper control parameters have been identified.

Original languageEnglish (US)
Pages (from-to)2121-2129
Number of pages9
JournalJournal of Micromechanics and Microengineering
Volume15
Issue number11
DOIs
StatePublished - Nov 1 2005

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microchannels
Microchannels
Bubbles (in fluids)
boiling
Boiling liquids
Heat flux
heat flux
Nucleation
bubbles
nucleation
flow velocity
Flow rate
syringes
Syringes
nucleate boiling
Nucleate boiling
forced convection
liquid flow
heat sinks
Forced convection

ASJC Scopus subject areas

  • Instrumentation
  • Materials Science(all)
  • Mechanics of Materials
  • Computational Mechanics

Cite this

Height effect on nucleation-site activity and size-dependent bubble dynamics in microchannel convective boiling. / Lee, Man; Cheung, Luthur Siu Lun; Lee, Yi Kuen; Zohar, Yitshak.

In: Journal of Micromechanics and Microengineering, Vol. 15, No. 11, 01.11.2005, p. 2121-2129.

Research output: Contribution to journalArticle

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